I have a 15 gallon tank that I'm planning on turning into a community tank of some sort. This is how it is currently stocked:

1 King betta (Leo)
4 Otocinclus catfish (possibly 5, one is unaccounted for at the moment)

I'm not sure what else I could put in there. Leo is a gentle giant, so might be able to tolerate some more colorful fish, though I'm willing to not push the boundaries. I'm open to options! Planning on maybe getting a few more otos, but won't be getting any other bottom feeder type fish.

I have two 40 gal Betta tanks, that also house 8-10 Platys.. ;) They live quite well together..

Make sure that you have somewhere for them to hide (e.g rocks or driftwood) and add some (fake or real) plants for cover..

Try to avoid getting all male Platys, especially in a smaller tank as they may have territorial battles to see who is the strongest / Alpha Male, so I would suggest one male and two or three females.. If you dont want them to breed, then just get 3 females, although if you do breed them, your Betta will help keep the population down.. ;)